The objectives of this proposed work is to determine what mechanisms on the surface of the host and bacteria govern the establishment of an acute and chronic bladder infection. Rat bladders studied by light and scanning electron microscopy. Competitive inhibition and enzymatic degradation of both urothlial and bacterial cell receptors will be studied to gather information on the chemistry of the receptors. The antibody response to pathogens will be studied by immunological techniques in an effort to determine the quantitative and qualitative immunological response. Antibody concentrations will be suppressed by azathioprine or enhanced by vaccination to determine their role in suppressing infections. Chronic urinary tract infections will be established in rats by surgically placing a foreign body in the bladder. Vaccination, chemical alteration of the bladder surface, blocking of bacterial adherence, antibody quantitation and localization will be attempted with this model to elucidate the host parasite relationships in chronic urinary tract infections. In addition, human urinary tract tissues will be compared and contrasted with the rat bladder models to compare and contrast human infections with those induced in the rat model.